Suspension for a disk drive including a load beam having a recess containing a damper, and method for manufacturing suspension

ABSTRACT

A suspension for supporting a magnetic head is provided with a load beam formed of a thin-plate spring. A recess for accommodating a damper is formed in the load beam. The damper is affixed to a bottom surface of the recess.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Divisional of U.S. application Ser. No. 12/704,712, filed Feb.12, 2010 (now U.S. Pat. No. 8,161,626), which application is based uponand claims the benefit of priority from prior Chinese Patent ApplicationNo. 200910006550.3, filed Feb. 17, 2009, the entire contents of both ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a load beam constituting a part of asuspension of a disk drive, suspension with the load beam, and amanufacturing method for the suspension.

2. Description of the Related Art

Conventionally, a magnetic disk device, such as a hard disk drive (HDD)or magneto-optical drive, comprises a magnetic head. The head fliesabove a magnetic disk rotating at high speed with a fine spacetherebetween. Data on the disk is read or written by the head.

An example of a suspension is disclosed in, for example, Jpn. Pat.Appln. KOKAI Publication No. 10-162532 or 9-91909.

In recent years, the head size and flying height (above the disksurface) have been reduced with the development of disk devices withhigher recording densities. In order to accurately read and writemagnetic disk data, it is important to suppress vibration of a headportion, thereby precisely positioning the head.

As shown in FIG. 10, a disk drive with a suspension generally comprisesa magnetic head 1, a suspension 2 supporting the head 1, a block 3 towhich the suspension 2 is fixed, etc. The suspension 2 generallycomprises a load beam 10 formed of a precise thin-plate spring, abaseplate 11, a flexure 12 formed of a plate spring thinner than theload beam 10, etc. The magnetic head 1 is located on a gimbal portionformed at the distal end of the flexure 12.

A head portion comprising the magnetic head 1 receives vibration from adevice for driving the head portion, a motor (not shown) for rotating adisk 13, etc. Thus, the suspension 2 formed of a plate spring, may bedeformed so that the magnetic head 1 is dislocated. This results in aread or write error. Thereupon, the damper 14, such as the one shown inFIG. 11, may be used to reduce or remove vibration of the suspension 2.The damper 14 is also referred to as a vibration damping member. Thedamper 14 comprises a metallic restrainer 15 and viscoelastic member 16of a viscoelastic material, which are laminated thickness-wise. Thedamper 14 is affixed to the load beam 10 of the suspension 2.

According to the suspension 2 with the damper 14, the viscoelasticmember 16 sandwiched between the vibrating suspension 2 and restrainer15 is deformed as the suspension 2 vibrates. Molecular friction of theviscoelastic member 16 produces internal resistance, thereby convertingvibrational energy into thermal energy. Thus, the vibrational energydirectly received by the suspension 2 is greatly reduced, so that avibration dumping effect can be obtained. FIG. 12A shows vibrationcharacteristics observed before the damper 14 is affixed to the loadbeam 10. FIG. 12B shows vibration characteristics observed after thedamper 14 is affixed to the load beam 10. As shown in FIG. 12B, adamping effect obtained from the damper 14 affixed to the load beam 10lowers the peak value of a gain in each vibration mode and provides thevibration damping effect.

As shown in FIGS. 3A and 4A, transversely opposite side edge portions 10a of the load beam 10 are bent in order to enhance the rigidity of theload beam 10. In this specification, the bending of the bent side edgeportions 10 a is referred to as “rib bending”. In order to maintain anappropriate flying height of the magnetic head 1 above the surface ofthe disk, moreover, a proximal portion 10 b of the load beam 10 isslightly bent, as viewed laterally relative to the load beam 10, asshown in FIG. 4A. The proximal portion 10 b is located near the block 3and also functions as a hinge portion for warping the load beam 10thickness-wise. In this specification, the bending of the proximalportion 10 b is referred to as “load bending”. If the damper 14 isaffixed to the load beam 10 before this load bending, it may undesirablyinterfere with a bending tool during the rib or load bending. In actualmanufacturing processes, therefore, the damper 14 is affixed to the loadbeam 10 after the load beam 10 is bent, as shown in FIGS. 9A to 9D.

In order to cause the viscoelastic member 16 to adhere closely to theload beam 10 in affixing the damper 14 to the load beam 10, however, thedamper needs to be pressed against the load beam 10 with a predeterminedload. In some cases, the load beam 10 may be deformed by a pressingforce on the damper 14 that is affixed to the bent load beam. If theload beam 10 is deformed, static properties, such as spring load, anddynamic properties, such as resonance, may vary. Variations of theseproperties impair the commodity value and working properties of thesuspension.

If the damper is dislocated with respect to the load beam when it isaffixed to the load beam, moreover, it may adversely affect theproperties of the suspension. Conventionally, it is difficult toaccurately position the damper, since the damper is affixed to the loadbeam formed of a flat thin-plate spring that carries no indication of adamper mounting position.

According to the conventional manufacturing processes in which thedamper is affixed to the bent load beam, the opposite side edge portions10 a that are bent like ribs hinder the operation for affixing thedamper 14. Since one damper 14 is affixed to each load beam 10,furthermore, the affixing operation is time-consuming, that is, workperformance is poor.

Conventionally, the viscoelastic member is sometimes caused to projectmuch from the periphery of the damper by the pressing force on thedamper that is affixed to the load beam. In such a case, it istroublesome and difficult to thoroughly remove a projecting part of theviscoelastic member. In some cases, the periphery of the viscoelasticmember is covered by a resin coating material after the damper isaffixed to the load beam. In these cases, the usage of the coatingmaterial is too much to reduce the weight of the load beam.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the object of the present invention is to provide a loadbeam having stable properties such that it is less deformed by a damperaffixed thereto, a suspension, and a manufacturing method for thesuspension.

A load beam of the invention is formed of a thin-plate spring andconstitutes a part of a suspension which supports a magnetic head, and arecess is formed in a part of the load beam so as to accommodate thedamper. The recess may be formed by either partial etching or pressing.Alternatively, the recess may be formed by boring a through-hole greaterthan the damper in one of two plates which are superposed to each otherto form the load beam. The depth of the recess should preferably begreater than the thickness of the damper.

A suspension according to the invention is the one which supports themagnetic head and comprises the above-described load beam, the damperbeing affixed to a bottom surface of the recess of the load beam.

In a method for manufacturing the suspension, the load beam is bentafter the damper is affixed to the bottom surface of the recess of theload beam.

Further, the suspension manufacturing method described above maycomprise fabricating a continuous load beam blank comprising a pluralityof the load beams from a thin-plate spring material, forming the recessfor accommodating the damper in each of the load beams of the load beamblank, affixing the damper to the bottom surface of the recess of eachof the load beams, and bending each of the load beams after the damperis affixed thereto and separating the load beam from a scrap portion ofthe load beam blank.

According to the present invention, as described above, the recessgreater than the damper is formed in the load beam, corresponding to aposition where the damper is affixed. The damper is contained in therecess. Thus, the damper can be prevented from interfering with abending tool even if the load beam is bent with the damper affixedthereto. Therefore, the damper can be affixed to the unbent flat loadbeam. Accordingly, the load beam cannot be easily deformed, so that thestatic and dynamic properties of the suspension can be prevented fromvarying. The recess should only be sufficiently large to accommodate thedamper. In consideration of the work performance for the affixture ofthe damper to the load beam and the projection of the viscoelasticmember, the recess should preferably be slightly larger than the damper.

The recess is formed by, for example, partial etching. Since the recessformed by partial etching can be used as a guide for the affixture ofthe damper, the damper can be easily positioned with respect to the loadbeam.

Since the damper can be affixed to the unbent flat load beam, moreover,the operation for affixing the damper can be easily automated. Since thedamper can be affixed to each load beam of the continuous load beamblank that comprises a plurality of unbent load beams, in particular,the damper affixing operation can be automated with higher speed andaccuracy and less deformation. In this case, the efficiency of thedamper affixing operation can be further improved.

As the damper is pressed against and affixed to the load beam, a part ofits viscoelastic member may sometimes be caused to project from theperiphery of the restrainer. According to the present invention,however, the damper is contained in the recess, so that the projectingpart of the viscoelastic member can be confined within a groove definedbetween the inner side surface of the recess and the side surface of thedamper. Thus, the viscoelastic member can be prevented from projectingoutside the load beam. Since the groove exists inside the recess,moreover, a coating material (e.g., resin) can be easily filled aroundthe damper, and the usage of the coating material can be reduced.

Thus, according to the present invention, the damper is contained in therecess formed in the load beam. The weight of the load beam itself canbe reduced by a margin corresponding to the recess. Consequently, anincrease in weight attributable to the presence of the damper can becompensated with a reduction of the weight of the load beam, so that thesuspension can be made lighter in weight.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1A is a plan view of a conventional suspension;

FIG. 1B is a plan view of a suspension according to one embodiment ofthe invention;

FIG. 2 is a partial sectional view typically showing a load beam anddamper of the suspension shown in FIG. 1B;

FIG. 3A is a sectional view of the suspension taken along line 3A-3A ofFIG. 1A;

FIG. 3B is a sectional view of the suspension taken along line 3B-3B ofFIG. 1B;

FIG. 4A is a sectional view of the suspension taken along line 4A-4A ofFIG. 1A;

FIG. 4B is a sectional view of the suspension taken along line 4B-4B ofFIG. 1B;

FIG. 5A is a sectional view showing how a viscoelastic member of adamper of the conventional suspension projects from the periphery of arestrainer;

FIG. 5B is a sectional view showing how a viscoelastic member of adamper of the suspension according to the invention projects from theperiphery of a restrainer;

FIG. 6A is a sectional view showing how the periphery of the damper ofthe conventional suspension is covered by a coating material;

FIG. 6B is a sectional view showing how the periphery of the damper ofthe suspension of the invention is covered by a coating material;

FIG. 6C is a sectional view showing another example of the load beam ofthe suspension of the invention;

FIG. 7A is a sectional view showing the load beam formed with a recessbefore bending work;

FIG. 7B is a sectional view showing the load beam shown in FIG. 7A andthe damper before affixture;

FIG. 7C is a sectional view showing how the damper shown in FIG. 7B isaffixed to the load beam;

FIG. 7D is a sectional view showing the load beam and damper after ribbending;

FIG. 8A is a plan view showing a load beam blank with recesses;

FIG. 8B is a plan view showing how each load beam of the load beam blankshown in FIG. 8A is provided with the damper;

FIG. 9A is a sectional view showing a conventional load beam beforebending work;

FIG. 9B is a sectional view showing the conventional load beam after thebending work;

FIG. 9C is a sectional view showing the conventional load beam and thedamper before affixture;

FIG. 9D is a sectional view showing how the damper is affixed to theconventional load beam;

FIG. 10 is a perspective view showing a part of a disk drive;

FIG. 11 is a sectional view showing a part of the damper;

FIG. 12A is a diagram showing vibration characteristics of a suspensionwithout a damper; and

FIG. 12B is a diagram showing vibration characteristics of a suspensionwith a damper.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the present invention will now be described withreference to the accompanying drawings.

FIG. 1A is a plan view of the suspension 2 comprising the conventionalload beam 10. FIG. 1B is a plan view of a suspension 2′ comprising aload beam 10′ according to the invention. FIG. 2 is a sectional viewtypically showing the load beam 10′ and a damper 14 according to theinvention. A recess 20 is formed in a part of the load beam 10′. FIG. 3Ais an enlarged sectional view taken along line 3A-3A of FIG. 1A. FIG. 3Bis an enlarged sectional view taken along line 3B-3B of FIG. 1B. FIG. 4Ais an enlarged sectional view taken along line 4A-4A of FIG. 1A. FIG. 4Bis an enlarged sectional view taken along line 4B-4B of FIG. 1B.

The load beam 10 shown in FIG. 3A is bent so that its transverselyopposite side edge portions 10 a rise like ribs. A central part of theconventional load beam 10 has a flat surface. In the load beam 10 shownin FIG. 4A, the proximal portion 10 b near the block 3 (FIG. 10) isslightly bent. In the conventional load beam 10, the damper 14 isaffixed to the flat surface between the side edge portions 10 a. Thus,in the conventional suspension 2, the damper 14 projects to a heightequal to its thickness above the flat surface of the load beam 10.

As shown in FIG. 3B, on the other hand, the load beam 10′ according tothe present invention is formed with the recess 20 larger than thedamper 14 in that part thereof on which the damper is located. The“recess greater than the damper” implies that the recess 20 is widerthan the damper 14 when the load beam 10′ is viewed vertically fromabove (FIG. 1B). The damper 14 is contained in the recess 20. The loadbeam 10′ is formed of a thin-plate spring. This thin-plate spring is aspringy stainless-steel plate with a thickness of, for example, 50 to100 μm.

As shown in FIG. 4B, a proximal portion 10 b of the load beam 10′ isslightly bent thickness-wise, as viewed laterally relative to the loadbeam. The proximal portion 10 b is located near the block 3 and alsofunctions as a hinge portion for warping the load beam 10′thickness-wise. The recess 20 is formed in a region including this hingeportion (or proximal portion 10 b). Thus, a part of the damper 14 islocated in the hinge portion (or proximal portion 10 b).

As shown in FIG. 11, the damper 14 comprises a metallic restrainer 15and viscoelastic member 16, which are laminated thickness-wise. Therestrainer 15 is affixed to a bottom surface 20 a of the recess 20 withthe viscoelastic member 16 between them. As shown in FIG. 2, the uppersurface of the restrainer 15, that is, a surface 14 a of the damper 14,is located within the recess 20. In other words, the surface 14 a of thedamper 14 does not project outside a surface 10 d of the load beam 10′.

According to the load beam 10′ of the present embodiment, therefore,interference of a bending tool with the damper 14 can be avoided whilethe load beam with the damper 14 thereon is being bent. Thus, the loadbeam 10′ can be bent after the damper 14 is affixed thereto. Inaddition, the recess 20 can be used as a positioning guide in affixingthe damper 14 to the load beam 10′. Accordingly, the damper 14 can beeasily positioned with respect to the load beam 10′.

In affixing the damper 14 to the bottom surface 20 a of the recess 20,the damper 14 is pressed against the load beam 10′. By this pressingforce, a part of the viscoelastic member 16 may sometimes be caused toproject from the periphery of the restrainer 15. In the case of theconventional suspension 2 shown in FIG. 5A, a part 16 a of theviscoelastic member projects much from the periphery of the restrainer15 if the pressing force on the damper 14 is heavy. Thus, an operationis needed to remove the projecting part 16 a of the viscoelastic member.

According to the load beam 10′ of the present invention, however, agroove 25 is formed between an inner side surface 20 b of the recess 20and the side surface of the restrainer 15, as shown in FIG. 5B. Thus,the part 16 a of the viscoelastic member projecting from the peripheryof the restrainer 15 is confined within the groove 25. Consequently, theoperation to remove the projecting part 16 a of the viscoelastic membercan be omitted.

Conventionally, as shown in FIG. 6A, the side surface of the damper 14is located outside the load beam 10, so that a considerable amount of acoating material 30 is used to cover the side surface of the damper.

According to the suspension of the present invention, however, a coatingmaterial 30 is filled into the groove 25 between the inner side surface20 b of the recess 20 and the damper 14 after the damper 14 is affixedto the bottom surface 20 a of the recess 20, as shown in FIG. 6B.Thereupon, the side surface of the damper 14 is covered by the coatingmaterial 30. Thus, the usage of the coating material 30 can be reducedcompared to the conventional case.

FIG. 8A shows a load beam blank 41 comprising a plurality of load beams10′ and scrap portions 40. The load beam blank 41 is formed by, forexample, etching. Each recess 20 should preferably be formed by partialetching as the load beam blank 41 is etched. Further, the recess 20 maybe formed by pressing.

Alternatively, as shown in FIG. 6C, each load beam 10′ may be formed bysuperposing two thin plates 50 and 51 on each other, and each recess 20may be formed by boring a through-hole 52 greater than each damper 14 inthe one plate 50.

Each load beam 10′ is bent with the damper 14 affixed to the bottomsurface 20 a of the recess 20. In order to avoid interference betweenthe bending tool and damper 14, a depth D1 (FIG. 2) of the recess 20should preferably be made greater than a thickness T1 of the damper 14.In this embodiment, the recess 20 is formed in that one of the obverseand reverse surfaces of the load beam 10′ which is located opposite froma flexure 12. Alternatively, however, the recess 20 may be formed in thesame surface as the flexure 12.

The following is a description of processes for manufacturing thesuspension with the load beam 10′. As shown in FIG. 7A, the recess 20 isformed in the load beam 10′ that is not yet bent. As shown in

FIG. 7B, thereafter, the damper 14 is opposed to the bottom surface 20 aof the recess 20. Then, the damper 14 is affixed to the bottom surface20 a of the recess 20, as shown in FIG. 7C. Thereafter, the rib bendingand load bending of the load beam 10′ are performed by means of thebending tool, e.g., a die set (not shown).

According to this embodiment, the damper 14 is affixed to the unbentflat load beam 10′ (FIGS. 7A to 7C). Therefore, rib-like opposite sideedge portions 10 a can be prevented from interfering with a device foraffixing the damper 14. Thus, the operation for affixing the damper 14to the load beam 10′ can be automated more easily than in the case ofthe conventional suspension 2 (FIG. 1A).

As shown in FIG. 8A, the continuous load beam blank 41 comprising theplurality of load beams 10′ may be formed by etching. As shown in FIG.8B, in this case, the damper 14 should be affixed to the recess 20 ofeach load beam 10′ of the load beam blank 41. By doing this, the damperaffixing operation can be automated with higher speed and accuracy andless deformation, so that the operation efficiency can be furtherimproved.

The present invention is not limited to the embodiment described herein,and its constituent elements may be embodied in various forms withoutdeparting from the scope or spirit of the invention. Further, theinvention is also applicable to suspensions of other disk drives thanhard disk drives.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A suspension configured for a disk drive tosupport a magnetic head, said suspension comprising: a load beam formedof a thin-plate spring, the load beam comprising a bent portion which isbent in a thickness direction when viewed laterally relative thereto,and having a recess formed in a region including the bent portion, and adamper contained in the recess of the load beam, the damper comprising arestrainer and a viscoelastic member laminated thereon, the restrainerbeing affixed to a bottom surface of the recess via the viscoelasticmember with the viscoelastic member being provided between the bottomsurface and the restrainer, and a groove which is a part of the recessand which is formed between an inner side surface of the recess and aside surface of the restrainer, wherein a part of the viscoelasticmember projecting from a periphery of the restrainer is provided betweenthe periphery of the restrainer and the inner side surface of therecess.
 2. The suspension according to claim 1, wherein the the bentportion forms a hinge portion.
 3. The suspension according to claim 1,wherein the recess comprises a partial etched recess.
 4. The suspensionaccording to claim 1, wherein the recess comprises a pressed recess. 5.The suspension according to claim 1, wherein the load beam comprises afirst plate which has a through-hole for the recess configured tocontain the damper, a size of the through-hole being-greater than a sizeof the damper, and a second plate superposed to the first plate.
 6. Thesuspension according to claim 1, wherein a depth of the recess isgreater than a thickness of the damper.